Lyndon Johnson reportedly said that ""the two worst things that can happen to a politician are to wake up with a live boy or a dead girl."" When the latter happens to David Cummings, a much-loved, cancer-stricken U.S. senator from Iowa, it sets off a chain of events and a clumsy thriller that boasts only a few moments of interest and excitement. Cummings's dark secret is his sexual attraction to underage girls, a bad habit that his chief aide--his smarter, tougher twin sister, Helen--has managed to hush up. But 15-year-old Darcy Fuller's death, after a fall from the senator's bed, threatens to end not only his career but Helen's, too: she plans on inheriting his seat after he dies. Conveniently, rich ne'er-do-well Richie McGuire has also been involved with Darcy, and the frequently drunk-and-disorderly young man makes the perfect fall guy. Inconveniently, Richie's protective big sister is the DA in the city of Crystal Falls. There's the germ of an original idea here--tough sisters fighting to defend weak brothers--but it's soon undermined by Gorman's graceless, jerky prose and grindingly predictable plotting. (Oct.)